Mentha spicata L. infusions as sources of antioxidant phenolic compounds: emerging reserve lots with special harvest requirements

Abstract

a Mentha spicata L., commonly known as spearmint, is widely used in both fresh and dry forms, for infusion preparation or in European and Indian cuisines. Recently, with the evolution of the tea market, several novel products with added value are emerging, and the standard lots have evolved to reserve lots, with special harvest requirements that confer them with enhanced organoleptic and sensorial characteristics.The apical leaves of these batches are collected in specific conditions having, then, a different chemical profile. In the present study, standard and reserve lots of M. spicata were assessed in terms of the antioxidants present in infusions prepared from the different lots. The reserve lots presented the highest concentration in all the compounds identified in relation to the standard lots, with 326 and 188 µg mL −1 of total phenolic compounds, respectively. Both types of samples presented rosmarinic acid as the most abundant phenolic compound, at concentrations of 169 and 101 µg mL −1 for reserve and standard lots, respectively. The antioxidant activity was higher in the reserve lots which had the highest total phenolic compounds content, with EC 50 values ranging from 152 to 336 µg mL −1 . The obtained results provide scientific information that may allow the consumer to make a conscientious choice.

Dehydration process influences the phenolic profile, antioxidant and antimicrobial properties of Galium aparine L.

“…The mixture was left to stand for 60 min in the dark and at room temperature. The absorbance was measured at 515 nm to assess the reduction of DPPH radicals, which was calculated as a percentage of DPPH discolouration using the formula: [(A DPPH − A S )/A DPPH ] × 100, where A S is the absorbance of the solution containing the sample, and A DPPH is the absorbance of the DPPH solution (Rita et al, 2016).…”

“…The supernatant (0.8 mL) was then poured in a 46-well microplate along with deionised water (0.8 mL) and ferric chloride (0.1% w/v). The reducing power was assessed through the absorbance at 690 nm, using the microplate reader mentioned above (Rita et al, 2016).…”

“…After 2 h of incubation at 50°C in a water bath with agitation (100 rpm), the absorbance (T1) was measured again. β-carotene bleaching inhibition was calculated using the equation: Absorbance (T1) − Absorbance (T0) × 100 (Rita et al, 2016).…”

Exploring reserve lots of Cymbopogon citratus , Aloysia citrodora and Thymus × citriodorus as improved sources of phenolic compounds

“…The dry material of the three species (A. citrodora, T. citriodorus, and C. citratus) used for infusions preparation, both standard and reserve lots, was provided by Cantinho das Aromáticas (organic farmers from Vila Nova de Gaia, Portugal). According to the information provided by the producers, reserve lots were prepared through different harvest procedures, in the hot summer months, being composed by the younger parts (apical leaves) of the species (Rita et al 2016).…”

“…Owing to this increasing consumption level, and in an attempt to meet consumers' requirements, tea companies have been introducing new added-value products with different characteristics (Gramza-Michałowska, Kulczyński, Xindi, & Gumienna, 2016). The so-called reserve lots, for example, are prepared through distinct harvesting techniques that differentiate them from standard lots, not only in terms of sensorial characteristics, but also regarding their chemical composition (Rita, Pereira, Barros, Santos-Buelga, & Ferreira, 2016).…”